Vehicle bodies are made of several layers of sheetmetal consisting of at least an interior wall and an exterior wall and sometimes another wall in between for more structure. When repairing the body it may be required to repair all of the layers not just the exterior layer.
Never dig into the body of a 45 year old car unless you are willing to fix the horrors it may expose. A small amount of rust or a repaint can’t hide the true degraded condition of what lies beneath.
We have the LT4 Wet Sump Automatic Connect & Cruise Powertrain System w/ 8 Speed transmission installed and running great in the Firebird. This engine has a 10:1 compression ratio, makes 9 pounds of boost, and produces 650 horsepower and 650 lb.-ft. of torque with 100 octane fuel. On our dyno with this configuration and running 91 octane for testing purposes we are seeing 541 horsepower and 613 lb-ft. of torque.